The present invention relates to optics and to the use of electrostatic and pneumatic actuators to correct the optics of mirrors, and in particular, thin filmed plastic mirrors such as Mylar mirrors.
Curved, aluminized Mylar mirrors are light weight and have found important applications in visual trainer systems. They have also been proposed and investigated for applications such as large, space-based telescopes where cost and weight are critical considerations. The methods proposed and utilized to date, to manufacture these mirrors depend upon stretching the Mylar over a pre-formed frame and drawing it into shape with a vacuum and/or air pressure. This however, typically leads to a certain amount of uncontrolled distortion. The problem is worse for space-based applications, where creases in the mirror due to packing are creating even more difficulties.
Attempts to solve this problem in the past have been limited to controlling the shape of the frame and the Mylar drawing schedule. A need therefore exists for an improved system to maintain and adjust the optics of a Mylar mirror.
The present invention involves the use of electrostatic and/or pneumatic actuators to correct the optics of Mylar mirrors, such as those used in visual trainer systems. The invention could also be implemented on thin filmed plastic mirrors other than Mylar, or glass or quartz mirrors.
A Mylar mirror is manufactured from a frame and a Mylar reflecting surface. An infrared generating source directs a laser or other infrared beam towards the mirror surface. The mirror surface reflects the laser, and the reflected beam is detected by an infrared sensor. An analog/digital conversion and processor unit analyses the reflected beam, calculations are performed with results converted to analog format and amplified. The electric potential is transmitted to electrodes which are attached to the frame of the mirror. The electric potential supplied to the electrodes, in conjunction with an electric potential supplied to the mirror surface, causes the Mylar reflecting surface to move, thereby adjusting the optics of the mirror. This process occurs on a segment by segment (of the mirror) basis, and is controlled by the analog/digital conversion and processor unit.
In another embodiment of the invention, chambers on the mirror are formed by the boundaries of the mirror frame, the Mylar mirror surface, and foam coffer dams disposed between the frame and mirror surface. A control valve connects each chamber to a vacuum source and/or a pressurized air source. By controlling a vacuum on the chamber, or supplying pressurized air to the chamber, the mirror surface which forms a boundary of that particular chamber moves towards the frame or away from the frame respectively, thereby adjusting the optics of the mirror.
Accordingly, it is an object of the present invention to provide a system and method to automatically and continuously adjust the optics of a mirror, and in particular, a thin filmed plastic mirror such as a Mylar mirror.
It is another object of the present invention to automatically and continuously adjust the optics of a thin filmed plastic mirror through the use of a processor-controlled infrared generating source.
It is a further object of the present invention to automatically and continuously adjust the optics of a thin filmed plastic mirror through the use of electrostatic actuators.
It is a still further object of the present invention to automatically and continuously adjust the optics of a thin filmed plastic mirror through the use of pneumatic actuators.
Briefly, these and other objects are satisfied by the invention disclosed in the following drawings and detailed description.